JP7432555B2 - engine - Google Patents

Description

The present invention relates to an engine, and more particularly, to an engine in which temperature rise in a belt tensioner is suppressed.

Conventionally, there is an engine that includes a cylinder head, an exhaust pipe assembled to the cylinder head, a heat shield cover covering the exhaust pipe, and a belt tensioner disposed on the side facing the end wall of the heat shield cover (for example, , see Patent Document 1).

JP2013-199880A (see Figure 5)

[Problem] The temperature of the belt tensioner tends to rise.
In the engine of Patent Document 1, the end wall of the heat shield cover and the belt tensioner face each other, and the temperature of the belt tensioner tends to rise due to radiant heat from the end wall of the heat shield cover.
An increase in the temperature of the belt tensioner causes thermal deterioration and damage, so it is necessary to avoid this.

An object of the present invention is to provide an engine in which a rise in temperature of a belt tensioner is suppressed.

The main configuration of the present invention is as follows.
As illustrated in FIG. 3, this engine includes an engine hanging fitting (23) assembled to the cylinder head (1) and a heat shield plate (24) along the end wall (21a) of the heat shield cover (21). The heat shield plate (24) is led out from the engine hanging fitting (23) and is arranged between the end wall (21a) of the heat shield cover (21) and the belt tensioner (22). engine.

The present invention has the following effects.
<<Effect>> The temperature rise of the belt tensioner (22) is suppressed.
In this engine, the radiant heat from the end wall (21a) of the heat shield cover (21) is blocked by the heat shield plate (24), and the heat accumulated in the heat shield plate (24) is transferred between the heat shield plate (24) and the engine hanging bracket. Since heat is radiated from both of the belt tensioner (23), the temperature rise of the belt tensioner (22) is suppressed.

FIG. 6 is a diagram illustrating a cooling structure for a delivery pipe of an engine according to an embodiment of the present invention, and is a sectional view taken along line II in FIG. 5 and a front view in which a water pump and an engine cooling fan are superimposed. 6 is a sectional view taken along line II-II in FIG. 5. FIG. 8 is a sectional view taken along line III-III in FIG. 7. FIG.

FIG. 1 is a front view of an engine according to an embodiment of the present invention. FIG. 5 is a side view of the intake side of the engine of FIG. 4; FIG. 5 is a side view of the exhaust side of the engine of FIG. 4;

FIG. 5 is a plan view of the engine of FIG. 4; 5 is a rear view of the engine of FIG. 4. FIG.

1 to 8 are diagrams for explaining an engine according to an embodiment of the present invention. In this embodiment, a vertical water-cooled in-line multi-cylinder dual fuel engine will be explained.

As shown in FIGS. 4 to 8, this engine includes a cylinder block (27), a cylinder head (1) assembled on the top of the cylinder block (27), and a cylinder assembled on the top of the cylinder head (1). A head cover (28) and a front case (29) assembled to the front side of the cylinder block (27) with the central axis (8a) of the crankshaft (8) oriented in the longitudinal direction, and a front case (29) assembled to the rear side of the cylinder block (27). It includes a flywheel housing (30) and an oil pan (31) assembled to the lower part of the cylinder block (27). As shown in FIG. 8, a flywheel (30a) is housed within the flywheel housing (30).
This engine includes an intake system, a fuel supply system, an ignition system, an exhaust system, a breather system, a water cooling system, and a lubrication system.

The intake system of this engine consists of an intake manifold (3) assembled on one side of the cylinder head (1) with the width direction of the engine as the lateral direction, as shown in FIG. 4, and an intake manifold (3) as shown in FIG. The throttle body (32) assembled to the front end of the collector part (3a) of 3), the gas mixer (6) assembled to the front part of the throttle body (32), and the gas mixer (6) shown in FIG. The air cleaner (33) is configured such that air (33a) from the air cleaner (33) is supplied to the intake manifold (3) via the gas mixer (6) and the throttle body (32) in that order.
As shown in FIG. 2, the intake manifold (3) includes a rectangular box-shaped collector portion (3a) installed in a direction parallel to the central axis (8a) of the crankshaft (8), and a collector portion (3a). It is equipped with a plurality of branch parts (3b) led out downward from the side, and each branch part (3b) communicates with the intake port (1a) of the cylinder head (1), and is connected to the air cleaner (33) shown in FIG. Air (33a) introduced into the collector part (3a) shown in FIG. 2 through the gas mixer (6) and throttle body (32) in order is distributed to each intake port (1a) through each branch part (3b). be done.
As shown in FIG. 2, all of the branch portions (3b) are formed in an L-shape when viewed in a direction parallel to the central axis (8a) of the crankshaft (8).
This engine is a four-cylinder engine, and has four branch portions (3b) and four intake ports (1a). The four branches (3b) are shown in FIGS. 5 and 7.

As shown in FIG. 7, the fuel supply system for this engine includes a liquid fuel tank (34), a liquid fuel supply pump (35), a delivery pipe (5), and a plurality of parts attached to the delivery pipe (5). Each fuel injector (4) is inserted into the cylinder head (1), and the liquid fuel (34a) in the liquid fuel tank (34) is delivered to the delivery pipe (5) by the liquid fuel supply pump (35). As shown in FIG. 2, liquid fuel (34a) is injected from each fuel injector (4) into air (33a) passing through each intake port (1a).
As shown in FIGS. 5 and 7, four fuel injectors (4) are arranged.
Gasoline is used as the liquid fuel (34a).

As shown in FIG. 1, the fuel supply system for this engine includes a liquefied gas fuel source (36), a vaporizer (37), a gas regulator (10), and a gas mixer (6). The liquefied gas fuel (36a) of ) is vaporized by the vaporizer (37) to become gas fuel (37a), the pressure of the gas fuel (37a) is regulated by the gas regulator (10), and the gas mixer (6) is supplied to the gas mixer (6). At step 6), the mixture is mixed with air (33a) from the air cleaner (33) to form an air-fuel mixture, and the air-fuel mixture is introduced into the collector portion (3a) of the intake manifold (3) from the throttle body (32) shown in FIG. , are distributed to each intake port (1a) shown in FIG. 2 via each branch part (3b).
A liquefied gas fuel cylinder is used as the liquefied gas fuel source (36) shown in FIG. As the liquefied gas fuel (36a), liquefied petroleum gas, liquefied natural gas, or other liquefied gas fuel can be used.

As shown in FIG. 1, the fuel supply system for this engine includes a fuel switching operation device (38) and an electronic control device (39), and based on the fuel switching operation of the fuel switching operation device (38), Under the control of the device (39), liquid fuel operation and gas fuel operation are mutually switched.
The fuel switching operation device (38) is a fuel switching operation lever (38a), and the electronic control device (39) is an engine ECU (39a). ECU is an abbreviation for electronic control unit.
The electronic control device (39) is electrically connected to the gas regulator (10) and the fuel injector (4), and when the fuel switching operation device (38) is turned on to the liquid fuel side, the metering valve of the gas regulator (10) (not shown) is closed, and the electromagnetic valve (not shown) of the fuel injector (4) is opened at a predetermined timing for a predetermined time, so that a predetermined amount of liquid fuel (34a) is injected at a predetermined timing. When liquid fuel operation is performed and the fuel switching operation device (38) is turned on to the gas fuel side, the solenoid valve of the fuel injector (4) is normally closed, and the metering valve of the gas regulator (10) is opened. When the valve is turned on, the metered gas fuel (37a) is supplied from the gas regulator (10) to the gas mixer (6), and gas fuel operation is performed.

As shown in FIG. 2, the ignition system for this engine includes an electronic control unit (39), an ignition coil (40), a spark plug (not shown), and a spark plug plug cap (13). Under the control of the control device (39), a high voltage generated by the ignition coil (40) causes a spark to be ejected from between the electrodes of each spark plug, igniting the mixture of liquid fuel or gas fuel in each cylinder (2). .
Each ignition coil (40) is integrally attached to each plug cap (13). Each plug cap (13) is connected to each spark plug. The spark plug is assembled into the cylinder head (1), and the electrode that produces the spark faces into each cylinder (2).

The exhaust system of this engine includes an intake manifold (3) assembled on one side of the cylinder head (1) shown in FIG. 7, and an exhaust manifold (20a) shown in FIG. 6 installed on the opposite side of the cylinder head (1). We are prepared.

As shown in FIG. 7, the breather device of this engine is equipped with a PCV system (11). PCV is an abbreviation for positive crankcase ventilation.
The PCV system (11) includes a breather chamber (42) placed in the cylinder head cover (28), a PCV valve (43) placed at the outlet of the breather chamber, and a blow-by gas outlet tube led out from the PCV valve (43). (44), the blowby gas inlet (3c) of the intake manifold (3) connected to the outlet end of the blowby gas outlet tube (44), and the air cleaner (33) and gas mixer (6) shown in FIGS. 1 and 4. The fresh air introduction case (12) is equipped with a fresh air introduction tube (45) led out from between the front case (45) and a fresh air introduction case (12) connected to the outlet end of the fresh air introduction tube (45). 29), it communicates with the crank chamber (2c) shown in FIG.

In the PCV system (11), during normal operation, blow-by gas (42a) flowing out from each cylinder (2) shown in Fig. 2 into the crank chamber (2c) is transferred from the breather chamber (42) shown in Fig. 7 to the PCV valve. (43) to the intake manifold (3), and the inside of the crank chamber (2c) shown in FIG. 2 is drawn from the fresh air outlet tube (45) shown in FIG. The inside of the case (29) is ventilated with fresh air (33b) introduced in sequence.

As shown in Fig. 1, the water cooling system for this engine includes a water pump (15), a cylinder cooling water jacket (2b), a head cooling water jacket (1b), a head cooling water outlet case (14), and a radiator. (16), a radiator inlet hose (18), a radiator outlet hose (19), and a bypass tube (14b).
The head cooling water outlet case (14) includes a thermostat chamber (14a), a thermostat valve (14d) housed in the thermostat chamber (14a), a radiator side outlet (14e), and a bypass side outlet (14f). There is. The water pump (15) also includes a bypass inlet case (15a).

As shown in FIG. 1, the radiator side outlet (14e) of the head cooling water outlet case (14) communicates with the hot water inlet of the radiator (16) via the radiator inlet side hose (18). The facility water outlet of is in communication with the facility water inlet (15c) of the water pump (15) via the radiator outlet side hose (19).
A bypass side outlet (14f) of the head cooling water outlet case (14) communicates with a bypass inlet case (15a) of the water pump (15) via a bypass tube (14b).

When the temperature of the engine cooling water (1c) flowing into the thermostat chamber (14a) from the head cooling water jacket (1b) shown in Fig. 1 is relatively low, the thermostat valve (14d) maintains the closed state and cools the engine. The engine cooling water (1c) pumped by the water pump (15) passes through the cylinder cooling water jacket (2b), the head cooling water jacket (1b), and the thermostat chamber (14a) of the head cooling water outlet case (14). Then, as shown by the arrow of the engine cooling water (14c), it is returned to the water pump (15) from the bypass inlet case (15a) via the bypass side outlet (14f) and the bypass tube (14b) in order, and is then returned to the water pump (15). By bypassing 16), the water temperature is quickly raised.

When the temperature of the engine cooling water (1c) flowing into the thermostat chamber (14a) from the head cooling water jacket (1b) shown in Figure 1 becomes relatively high (80°C or higher), the thermostat valve (14d) is fully opened. The engine cooling water (1c) pumped by the cooling water pump (15) is sent to the cylinder cooling water jacket (2b), the head cooling water jacket (1b), and the thermostat chamber of the head cooling water outlet case (14). 14a), the engine cooling water (1c) is passed through the radiator outlet (14e), the radiator inlet hose (18), the radiator (16), and the radiator outlet hose (19) in order as shown by the arrow. The water is returned to the water pump (15) and cooled by heat dissipation by the radiator (16).

The radiator (16) shown in FIG. 1 is air-cooled by engine cooling air generated by an engine cooling fan (7).
As shown in FIG. 4, the fan pulley (7e) of the engine cooling fan (7) is driven from the crank pulley (8b) via the fan belt (8c), and the fan belt (8c) is driven by the belt tensioner (22). Tension is adjusted.
The belt tensioner (22) has an upper end that swings about a fulcrum (22a) at the lower end, and is fixed to a stay (22b) at a predetermined swing position.
The tension pulley (22c) of the belt tensioner (22) is covered from the side with a belt cover (22d).

As shown in FIG. 4, the lubricating system for this engine includes an oil pump (46) disposed inside the front case (29) and an oil filter (47) mounted on the side of the front case (29). and an oil cooler (48), and an oil gallery (not shown) formed in the cylinder block (27), so that the engine oil (not shown) in the oil pan (31) is pumped by the oil pump (46). The oil passes through an oil filter (47) and an oil cooler (48), and is supplied from the oil gallery to sliding parts such as a bearing (not shown) of the crankshaft (8).

As shown in FIG. 1, this engine includes a plurality of fuel injectors (4), a delivery pipe (5) that distributes liquid fuel (34a) to the plurality of fuel injectors (4), and a gas mixer (6). Liquid fuel operation and gas fuel operation are mutually switchable, and during liquid fuel operation, liquid fuel (34a) is injected from the fuel injector (4) into the air (33a) shown in FIG. 2 to form an air-fuel mixture. During gas fuel operation, air (33a) and gas fuel (37a) are mixed in the gas mixer (6) shown in FIG. 1 to form an air-fuel mixture.
This type of engine has the advantage that the user can select a fuel that is easy to handle for operation, and when a clean image is required, the user can select and use a gas fuel such as LPG, which has a clean image.

As shown in Figure 1, this engine is equipped with an axial engine cooling fan (7), and when viewed parallel to the central axis (8a) of the crankshaft (8), the entire delivery pipe (5) is are arranged at a position overlapping with the blades (7a) of the engine cooling fan (7), the area around the delivery pipe (5) is used as the air passage (9), and the end of the collector section (3a) of the intake manifold (3) A gas mixer (6) is attached, and this gas mixer (6) faces the ventilation inlet (9a) of the ventilation path (9) from the surrounding side (above).

As shown in Fig. 1, in this engine, a large amount of engine cooling air (7f) generated by the engine cooling fan (7) flows into the air passage (9) around the delivery pipe (5) that overlaps with the blade (7a). It is possible to suppress the temperature rise of the liquid fuel (34a) that is supplied to the fuel tank and stagnates in the delivery pipe (5) during gas fuel operation.

As shown in Fig. 1, the engine cooling air (7f) supplied to the air inlet (9a) of the air passage (9) is directed around (upwards) around the air inlet (9a) by the gas mixer (6). Since diffusion is suppressed, the amount of engine cooling air (7f) that cools the delivery pipe (5) becomes relatively large.
As shown in Fig. 1, during engine operation, the gas mixer (6) receives radiant heat from the cylinder head (1), and during gas fuel operation, the gas mixer (6) receives radiant heat from the cylinder head (1) during engine operation. Since the engine cooling air (7f) guided by the surface of the gas mixer (6) is cooled by the gas mixer (6) and its surface temperature is maintained at a relatively low temperature, the engine cooling air (7f) is supplied to the air passage (9) without increasing its temperature. .
In addition, since the delivery pipe (5) is arranged between the intake manifold (3) and the cylinder head cover (28), which have a relatively low surface temperature, the temperature rise of the liquid fuel (34a) due to radiant heat from these is small. There are hardly any.

As shown in Fig. 1, in this engine, the gas mixer (6) suppresses the diffusion of the engine cooling air (7f) in the circumferential direction (upward direction) of the air inlet (9a). It can also be used as a diffusion prevention component for engine cooling air (7f).

As shown in FIG. 2, in this engine, the peripheral wall (5a) of the delivery pipe (5) is formed of sheet metal.
In this engine, the delivery pipe (5) can be made slender compared to the one made of cast metal, and the heat capacity can be reduced, and the surrounding air passage (9) can be widened, allowing the liquid to stagnate in the delivery pipe (5). The cooling efficiency of the fuel (34a) is increased.

As shown in Fig. 2, in this engine, the peripheral wall (5a) of the delivery pipe (5) is a rectangular cylinder, and the fuel injector (4) is attached to one side (diagonally lower side), and the remaining three sides are is facing the ventilation duct (9).
In this engine, the peripheral wall (5a) of the delivery pipe (5) has a large heat dissipation area, increasing the cooling efficiency of the liquid fuel (34a) stagnant in the delivery pipe (5).

As shown in Fig. 1, in this engine, when viewed in a direction parallel to the central axis (8a) of the crankshaft (8), the delivery pipe (5) is located on the tip side of the blade (7a) of the engine cooling fan (7). It is placed in a position that overlaps with the half.
In this engine, a large amount of engine cooling air generated in the tip half of the blade (7a), which has a high rotational speed, is supplied to the air passage (9) around the delivery pipe (5), and inside the delivery pipe (5). The cooling efficiency of the stagnant liquid fuel (34a) is increased.

As shown in FIG. 1, in this engine, a gas regulator (10) is connected to a gas mixer (6), and this gas regulator (10) is connected to the air inlet (9a) of the air passage (9) on the surrounding side (above). It is coming from.

In this engine, the engine cooling air supplied to the air inlet (9a) of the air passage (9) is suppressed from dispersing in the circumferential direction (upward direction) of the air inlet (9a) by the gas regulator (10). Therefore, the amount of engine cooling air (7f) that cools the delivery pipe (5) becomes relatively large.
The gas regulator (10), which receives radiant heat from the cylinder head (1) during engine operation, is cooled by the gas fuel (37a) passing inside during gas fuel operation, and its surface temperature is relatively low. The engine cooling air, which is maintained at a low temperature and whose diffusion is suppressed on the surface of the gas regulator (10), is supplied to the air passage (9) without a rise in temperature.

In addition, in this engine, the gas regulator (10) suppresses the diffusion of the engine cooling air (7f) in the circumferential direction (upward direction) of the air blowing inlet (9a), so the gas regulator (10) It can also be used as a diffusion prevention component (7f).

As shown in Fig. 1, this engine is equipped with a fresh air introduction case (12) of the PCV system (11), and this fresh air introduction case (12) is placed in the air inlet (9a) of the air passage (9) around it. It is facing from the side (bottom side).

In this engine, the engine cooling air (7f) supplied to the air inlet (9a) of the air passage (9) is diffused in the circumferential direction (downward) of the air inlet (9a) by the fresh air introduction case (12). Therefore, the amount of engine cooling air (7f) that cools the delivery pipe (5) becomes relatively large.
Note that during engine operation, the surface of the fresh air introduction case (12), which receives radiant heat from the cylinder head (1), is cooled by the fresh air (33b) passing through the interior during engine operation, and its surface temperature decreases. The engine cooling air (7f), which is maintained at a relatively low temperature and whose diffusion is suppressed on the surface of the fresh air introduction case (12), is supplied to the air passage (9) without a rise in temperature.

In addition, in this engine, the fresh air introduction case (12) suppresses the diffusion of the engine cooling air (7f) in the circumferential direction (downward) of the air inlet (9a), so the fresh air introduction case (12) is It can also be used as a diffusion prevention component for engine cooling air (7f).

As shown in FIGS. 1 and 2, this engine includes a plug cap (13) of the spark plug, and the outer peripheral surface of the plug cap (13) of the spark plug faces the air passage (9).
In this engine, the plug cap (13) of the spark plug is cooled by the engine cooling air (7f) passing through the air passage (9), thereby suppressing thermal damage and thermal deterioration of the spark plug and the plug cap (13).

As shown in FIG. 1, this engine includes a head cooling water outlet case (14) attached to the cylinder head (1), and when viewed parallel to the central axis (8a) of the crankshaft (8), Assuming a fan center imaginary line (7c) that is parallel to the cylinder center axis (2a) and passing through the rotation center (7b) of the engine cooling fan (7), and with the fan center imaginary line (7c) as the boundary, the delivery pipe If we assume that the exhaust side ventilation area (7d) is located on the opposite side to the ventilation inlet (9a) of the intake side ventilation passage (9) around (5), the exhaust side ventilation area (7d) A head cooling water outlet case (14) is arranged.

In this engine, the heat of the head cooling water outlet case (14) is absorbed by the engine cooling air (7g) passing through the exhaust side ventilation area (7d), and is difficult to flow into the intake side airflow path (9). Therefore, the cooling efficiency of the liquid fuel (34a) stagnant in the delivery pipe (5) is increased.
Note that during engine operation, high-temperature engine cooling water (1c) immediately after flowing out from the cylinder head (1) passes through the head cooling water outlet case (14), so the surface of the head cooling water outlet case (14) Although the temperature is relatively high, the heat does not easily flow into the air passage (9) on the intake side.

As shown in FIG. 1, this engine includes a thermostat chamber (14a) provided in a head cooling water outlet case (14), a bypass tube (14b) led out from the thermostat chamber (14a), and a bypass tube (14b). ), the engine cooling water (14c) in the thermostat chamber (14a) bypasses the radiator (16) and is connected to the bypass inlet case (15a) of the water pump (15). (15a) is configured to be sucked into the inside.
As shown in FIG. 1, in this engine, the engine cooling fan (7) includes a blade mounting board (7h) on the center side, and blades (7a) projecting radially from the periphery of the blade mounting board (7h). When viewed in a direction parallel to the crankshaft (8), the bypass inlet case (15a) of the water pump (15) is arranged at a position overlapping the blade mounting board (7h) of the engine cooling fan (7).

In this engine, the heat from the bypass inlet case (15a) of the water pump (15) does not easily flow into the intake air passage (9), so the liquid fuel (34a) stagnates in the delivery pipe (5). Cooling efficiency increases.
Note that during engine operation, high-temperature engine cooling water (14c) immediately after flowing out from the head cooling water outlet case (14) passes through the bypass inlet case (15a) of the water pump (15). ) becomes relatively high, but the heat of the bypass inlet case (15a) that overlaps with the blade mounting board (7h) of the engine cooling fan (7) is difficult to transfer to the engine cooling air (7f), and the heat on the intake side It is difficult to flow into the air duct (9).

As shown in Fig. 1, it is equipped with a facility water inlet pipe (15b) attached to the bypass inlet case (15a) of the water pump (15) and a head cooling water jacket (1b) of the cylinder head (1). The engine cooling water (1c) from the water jacket (1b) passes through the radiator (17a) of the air conditioner (17) and flows from the facility water inlet pipe (15b) to the bypass inlet case (15a) of the water pump (15). It is configured to be suctioned.
As shown in Fig. 1, the facility water inlet is located closer to the delivery pipe (5) than the thermostat chamber (14a) and the bypass inlet case (15a) when viewed in a direction parallel to the central axis (8a) of the crankshaft (8). A pipe (15b) is arranged.

In this engine, during engine operation, radiant heat from the relatively high-temperature thermostat chamber (14a) and the bypass inlet case (15a) is blocked by the relatively low-temperature facility water inlet pipe (15b), which is closer to the delivery pipe (5). Since the engine cooling air (7f) passing through the air inlet (9a) is not heated, the cooling efficiency of the liquid fuel (34a) stagnant in the delivery pipe (5) is increased.
Note that while the air conditioner (17) is dissipating heat, the surface temperature of the facility water inlet pipe (15b) becomes relatively low due to the facility water (17b) passing through the facility water inlet pipe (15b), and the air conditioner During the heat radiation stop (17), the surface temperature of the facility water inlet pipe (15b) becomes relatively low due to stagnant water in the facility water inlet pipe (15b), so the relatively high temperature thermostat room (14a) and It blocks radiant heat from the bypass inlet case (15a) and suppresses heating of the engine cooling air (7f) passing through the air blowing inlet (9a).

As shown in FIG. 3, this engine includes a cylinder head (1), an exhaust pipe (20) assembled to the cylinder head (1), and a heat shield cover (21) that covers the exhaust pipe (20) from the surrounding area. and a belt tensioner (22) disposed on the side facing the end wall (21a) of the heat shield cover (21).
As shown in Fig. 3, this engine has an engine hanging bracket (23) attached to the cylinder head (1) (closer to the front) and an end wall (21a) (front) of the heat shield cover (21). The heat shield plate (24) is led out from the (front) engine hanging bracket (23) and is connected to the (front) end wall (21a) of the heat shield cover (21). It is arranged between the belt tensioners (22).
The exhaust pipe (20) is an exhaust manifold (20a).

In this engine, the radiant heat from the (front) end wall (21a) of the heat shield cover (21) is blocked by the heat shield plate (24), and the heat accumulated in the heat shield plate (24) is Since heat is radiated from both the engine suspension fitting (23) and the (front) engine hanging fitting (23), it is possible to suppress the temperature rise of the belt tensioner (22).

As shown in FIG. 7, the (front) hanging fitting (23) is placed near the front of the cylinder head (1), and this engine is located on the diagonal of the cylinder head (1) in plan view. It has a hanging fitting (23) (on the front) and an engine hanging fitting (23c) on the rear side, which faces it.

As shown in FIG. 4, this engine is equipped with an axial flow type engine cooling fan (7), and when viewed in a direction parallel to the central axis (8a) of the crankshaft (8), the engine cooling fan (7) is An engine hanging fitting (23) (closer to the front) is arranged at a position overlapping the blade (7a).
In this engine, the engine cooling air (7g) generated by the engine cooling fan (7) is directed to a ventilation area (7d) on the exhaust side around the engine hanging fitting (23) that overlaps with the blade (7a) (closer to the front). This can promote heat dissipation from the engine suspension fitting (23) (located near the front).

As shown in FIGS. 3 and 4, in this engine, the engine hanging fitting (23) (on the front side) is a straight guide part ( 23a), and a cooling air receiving part (23b) bent from the edge of the straight guide part (23a).
In this engine, the engine cooling air (7g) is received by the cooling air receiving part (23b), and heat dissipation from the engine hanging fitting (23) is promoted.
Further, in this engine, the strength of the (front) engine hanging fitting (23) can be increased by bending the cooling air receiving part (23b) from the straight guide part (23a).

As shown in FIG. 3, in this engine, the heat shield plate (24) has an extension part (24a) ( As shown in FIG. 4, an engine cooling fan (7) is provided between the cylinder head (1) and the belt tensioner (22) when viewed in a direction parallel to the central axis (8a) of the crankshaft (8). ) is provided with a cooling air introduction gap (25) that overlaps with the blade (7a).
As shown in Fig. 4, in this engine, the engine cooling air (7g) generated by the engine cooling fan (7) flows from the cooling air introduction gap (25) overlapping the blade (7a) to the exhaust side air blowing area (7d). Since the heat of the heat shield plate (24) is radiated from the wide heat radiation surface expanded by the extension parts (24a) and (24b) shown in FIG. 3, the heat radiation efficiency of the heat shield plate (24) is improved. is high.
The extension parts (24a) and (24b) consist of an upper extension part (24a) and a lower extension part (24b).

As shown in FIG. 3, in this engine, the extension (24a) of the (upper) heat shield plate (24) is bent toward the downstream side in the air blowing direction of the air passage (9) of the engine cooling fan (7). and is inclined with respect to the air blowing direction of the air blowing passage (9b) on the exhaust side.
In this engine, the slope of the (upper) extension part (24a) reduces the flow resistance of the exhaust side air passage (9b), and the heat shield plate (24) in the exhaust side air passage (9b) decreases. Cooling efficiency increases.

As shown in FIG. 3, in this engine, the belt tensioner (22) is a generator (26).
In this engine, the temperature rise of the generator (26), which is susceptible to thermal deterioration and thermal damage, is suppressed, so that the effect of suppressing thermal deterioration and thermal damage becomes apparent.
An alternator is used for the generator (26).

(1)...Cylinder head, (1a)...Intake port, (1b)...Head cooling water jacket, (1c)...Engine cooling water, (1d)...Engine cooling water, (2)...Cylinder, (2a)...Cylinder Center axis, (2b)...Cylinder cooling water jacket, (2c)...Crank chamber, (3)...Intake manifold, (3a)...Collector section, (3b)...Branch section, (3c)...Blow-by gas inlet, ( 4)...fuel injector, (5)...delivery pipe, (5a)...peripheral wall, (5b)...liquid fuel, (6)...gas mixer, (7)...engine cooling fan, (7a)...blade, (7b)... Center of rotation, (7c)...Fan center imaginary line, (7d)...Exhaust side ventilation area, (7e)...Fan pulley, (7f)...Engine cooling air, (7g)...Engine cooling air, (7h)...Base, (8)...Crankshaft, (8a)...Center axis line, (9)...Blower passage, (9a)...Blower inlet, (9b)...Blower passage on the exhaust side.

(10)...Gas regulator, (11)...PCV system, (12)...Fresh air introduction case, (13)...Plug cap, (14)...Head cooling water outlet case, (14a)...Thermostat chamber, (14b) ...Bypass tube, (14c)...Engine cooling water, (14d)...Thermostat valve, (14e)...Radiator side outlet, (14f)...Bypass side outlet, (15)...Water pump, (15a)...Bypass inlet case, (15b)...Facility water inlet pipe, (15c)...Facility water inlet, (16)...Radiator, (16a)...Facility water, (17)...Air conditioner, (17a)...Radiator, (18)...Radiator Inlet side hose, (19)...Radiator outlet side hose.

(20)...exhaust pipe, (21)...heat shield cover, (21a)...end wall, (22)...belt tensioner, (22a)...fulcrum, (22b)...stay, (22c)...tension pulley, (22d)... )...belt cover, (23)...front engine hanging bracket, (23a)...straight guide section, (23b)...cooling air receiving section, (23c)...rear engine hanging bracket, (24)...heat shield Plate, (24a)...extension part, (24b)...extension part, (25)...cooling air introduction gap, (26)...generator, (27)...cylinder block, (28)...cylinder head cover, (29)... front case.

(30)...flywheel housing, (31)...oil pan, (32)...throttle body, (33)...air cleaner, (33a)...air, (33b)...fresh air, (34)...liquid fuel tank, ( 34a)...liquid fuel, (35)...liquid fuel supply pump, (36)...liquefied gas fuel source, (36a)...liquefied gas fuel, (37)...vaporizer, (37a)...gas fuel, (38)...fuel Switching operation device, (38a)...Fuel switching operation lever, (39)...Electronic control device, (39a)...Engine ECU.

(40)...Ignition coil, (42)...Breather chamber, (42a)...Blowby gas, (43)...PCV valve, (44)...Blowby gas outlet tube, (45)...Fresh air outlet tube, (46)... Oil pump, (47)...Oil filter, (48)...Oil cooler.

Claims (6)

A cylinder head (1), an exhaust pipe (20) assembled to the cylinder head (1), a heat shield cover (21) that covers the exhaust pipe (20) from its periphery, and an end wall of the heat shield cover (21). In an engine equipped with a belt tensioner (22) disposed on the side opposite to (21a),
The engine hanging bracket (23) assembled to the cylinder head (1) and the heat shield plate (24) along the (front) end wall (21a) of the heat shield cover (21) are provided. An engine characterized in that it is led out from an engine hanging fitting (23) and placed between an end wall (21a) of a heat shield cover (21) and a belt tensioner (22). The engine according to claim 1,
The engine hanging bracket (23) includes a straight guide part (23a) along the air blowing direction of the exhaust side air passage (9b) of the engine cooling fan (7), and a cooling part bent from the edge of the straight guide part (23a). An engine characterized by being equipped with a wind catcher (23b). The engine according to claim 2,
The engine hanging bracket (23) includes a straight guide part (23a) along the air blowing direction of the air passage (9) of the engine cooling fan (7), and a cooling air receiving part bent from the edge of the straight guide part (23a). (23b). In the engine according to claim 2 or claim 3,
The heat shield plate (24) includes extension parts (24a) and (24b) that extend outward in the circumferential direction from the peripheral edge of the end wall (21a) of the heat shield cover (21), and extends from the peripheral edge of the end wall (21a) of the heat shield cover (21). A cooling air introduction gap (25) that overlaps with the blades (7a) of the engine cooling fan (7) is provided between the cylinder head (1) and the belt tensioner (22) when viewed in a direction parallel to the central axis (8a). An engine that is characterized by: The engine according to claim 4,
The extension part (24a) of the heat shield plate (24) is bent toward the downstream side in the blowing direction of the airflow path (9) of the engine cooling fan (7), and is bent toward the downstream side in the airflow direction of the airflow path (9b) on the exhaust side. The engine is characterized by being tilted. The engine according to any one of claims 1 to 5,
An engine characterized in that the belt tensioner (22) is a generator (26).

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